ATA 38 - WATER AND WASTE

• Toilet uses potable water to rinse toilet bowls.

• Each lavatory has its water manual shut-off valve.

• When water tank is full water gets ejected overboard from overflow duct.

• FWD DRAIN → Used to drain stagnating water in the forward fuselage section when in icing condition.

• Water servicing can be performed even without electrical power.

• Toilet system’s vacuum generator operates below 16000 ft, above that altitude differential pressure is enough to drag waste from toilet to waste tank.

• If toilet servicing panel is open, toilet flushing is inhibited.

Toilet flushing is also inhibited when waste tank’s liquid level transmitter senses full tank.

• If water tank’s Fill/Drain Valve is open, APU Bleed is inhibited

• Toilet servicing panel is located on R/H side, tail cone section (Frame 55-56).

• Both Water system and Waste system are controlled by DEU B → CIDS Directors → FAP.

• Waste Tank Sensors:

- Liquid Level Transmitters → Hydrostatic type

- Liquid Level Sensors → Ultrasonic type

• The potable water tank and the waste holding tank are installed in the pressurized underfloor area LH rear the aft cargo compartment (valid for 318,319,321) (A320 tank it is in fwd cargo). (Air pressurized system compressor is optional)

• Optionally, the fill/drain nipple and overflow nipple are also electrically heated.

These heating elements are controlled automatically by two anti-ice control units installed in

the cargo compartments.

• On A320 aircrafts, two drain valves are electrically controlled when the fill/drain control handle is set to the drain position.

• The Vacuum System Controller (VSC)(CLASSIC) controls the flushing system operation and stops the operation when the waste servicing panel is open. On enhanced systems, the vacuum toilet system is connected to the Cabin Intercommunication Data System (CIDS). The potable water tank has a capacity of 200 l (53 US gal). In each lavatory, a water heater is installed under the wash basin. If the quantity transmitter detects a low level into the water tank, it cuts the electrical supply of the water heater.

• When the FLUSH switch is pressed, the flush control unit initiates the flush sequence. The vacuum generator starts to operate and after 1.6 seconds the water valve opens for 1.7 seconds.

Then, the flush valve, controlled by the flush control unit, opens for 4 seconds to evacuate the waste

material through differential pressure. (16000 ft diff pressure is sufficient)

• Toilet Flush Control Unit (FCU) → Vacuum System Controller (VSC) → Waste Tank

• The toilet system is monitored by the Vacuum System Controller (VSC) function, which is integrated inside the Cabin Intercommunication Data System (CIDS) director (DIR).

• A CAUTion amber button, located in the upper left corner of the touchscreen, comes on and flashes when CIDS receives a message which cannot be shown immediately.